3-Isopropyl-2,6-bis(4-methoxyphenyl)piperidin-4-one

In the title compound, C22H27NO3, the piperidine ring adopts a slightly distorted chair conformation. The dihedral angle between the two aromatic rings is 60.4 (1)°. In the crystal, the amino group forms a rather long N—H⋯O contact to a methoxy O atom. There are also C—H⋯O interactions present.

In the title compound, C 22 H 27 NO 3 , the piperidine ring adopts a slightly distorted chair conformation. The dihedral angle between the two aromatic rings is 60.4 (1) . In the crystal, the amino group forms a rather long N-HÁ Á ÁO contact to a methoxy O atom. There are also C-HÁ Á ÁO interactions present.

Comment
In the family of heterocyclic compounds, piperidin-4-ones possess varied biological properties such as antiviral, antitumour (El-Subbagh et al., 2000), analgesic (Jerom & Spencer, 1988), local anaesthetic (Perumal et al., 2001;Hagenbach & Gysin, 1952), anti-inflammatory and anticancer activities (Katritzky & Fan, 1990). Several 2,6disubstituted piperidines are found to be useful as tranquillisers (Bochringer & Soehne, 1961) and possess hypotensive activity (Severs et al., 1965), a combination of stimulant and depressant effects on the central nervous system (Ganellin & Spickett, 1965). Also the substitution of methoxy phenyl groups at 2,6-positions is found to be active against CNS subpanels. In addition, the bulkiness of the subtituent in different positons of the piperidine ring leads to the decrease in carcinogenecity (Ravindran et al., 1991). In view of the importance, the crystallographic study of the title compound has been carried out to establish the molecular structure and conformation.
The packing of the molecules is stabilized by a rather long N-H···O contact and by C-H···O interactions in addition to van der Waals forces.

Experimental
Ammonium acetate (100 mmol), anisaldehyde (200 mmol) and isobutylmethylketone (100 mmol) in ethanol (30 ml) were heated on a hot plate at 50-55° C and after the completion of reaction, water was added and extracted with ether, dried and recrystallized from ethanol.

Refinement
Due to the absence of anomalous scatterers, the absolute configuration could not be determined and Friedel pairs were merged. C-bound H atoms were positioned geometrically (C-H = 0.93-0.97 Å) and allowed to ride on their parent atoms, with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (C) for all other H atoms. The H atom bonded to N was freely refined. program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figure 1
The molecular structure of the title compound, showing the atomic numbering and displacement ellipsoids drawn at 30% probability level. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.